Optimization of imazalil removal in the system UV/TiO2/K2S2O8 using a response surface methodology (RSM) Review Article

Authors: R. Hazime, Q.H. Nguyen, C. Ferronato, T.K.X. Huynh, F. Jaber, J.-M. Chovelon

Abstract:
The optimization of the photocatalytic degradation of a carcinogen pesticide, imazalil, was carried out in an aqueous solution using TiO₂ as photocatalyst under UV irradiation in the presence of persulfate. Persulfate plays a double role; an electron scavenger and it promotes the formation of sulfate radicals which allow accelerating the removal of imazalil.   
     For the optimization, experimental design was used based on the surface response methodology; it was applied to assess the individual and interaction effects of several operating parameters (pH, TiO₂ concentration, pesticide concentration and persulfate concentration) on the treatment efficiency (90% of pesticide removal time).
    Based on the experimental design data, a semi-empirical expression was obtained, permitting to predict and to optimize the pesticide removal time. This model was very consistent with experimental results (correlation factor: 99.15%). The strongest interactions between the parameters assessed were pH/[K₂S₂O₈] and [Imazalil]/[K₂S₂O₈]. Optimal experimental conditions found for imazalil (25 mg L⁻¹) removal were acidic pH 3–4, persulfate concentration (≈2.5 g L⁻¹) and TiO₂ loading (2.5 g L⁻¹). By using tert-butanol as hydroxyl radical scavenger, it was found that sulfate radicals were predominant at acidic pH and as the pH increases the hydroxyl radicals are more and more produced.
   The experimental design allows obtaining the maximum of efficiency with the minimum amount of persulfate.
    This work demonstrates wellthe utility and benefits ofthe experimental design approach for screening and modeling the reaction parameters.
      Furthermore, it contributes significantly to the improvement and better understanding of photocatalytic processes using oxidants.

Keywords:
Imazalil degradation
UV/TiO₂/K₂S₂O₈
CCD
Experimental design
Persulfate

Published in: Applied Catalysis B: Environmental (Volumes 132–133, Pages 1-552, 27 March 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Optimization of imazalil removal in the system UV/TiO2/K2S2O8 using a response surface methodology (RSM) Review Article

Bình luận của bạn

*

*

*

*

 Captcha

Gửi bình luận nhập lại